On either, you will get EDGE speed.
You will have WiFi on the Bold.
I've used both and like both devices, you can't beat the large hi-res screen on the Storm, but you can't beat the WiFi speed on the Bold, either.

I too have used both on the tmo network. I couldn't handle the touch screen on the storm I'm too old school I guess. I'm currently using the bold on tmo. I concur with the above post, with either will not have 3g. When the 8900 comes out on tmo I'll get it. I need the uma to have good service at home.

Storm is a great device once you spend some time with it. It's not the same as any other blackberry you have used, it take time to get used to. I have no regrets with mine and have a friend who runs his on TMO ... Tough Choice indeed.

I have only had it for a few days now, but the storm is a completely different animal then the other BB. the bold is a nice device w the latest technology but w the storm it just feels different. with the bold you will have the familiar track ball, key board, its just a big curve for me. w the storm everything is different, and i guess i really needed a change from the typical BB devices, and w the storm i have that.